Redundancy No system is a good system unless it is a redundant system. Our entire architecture – databases, servers, local- and wide-area networks and transport systems – is redundant. In fact, ComTrust maintains a dual data operating center (dual DOC) configuration to deliver your directory assistance services. Both DOCs contain fully redundant databases and both are in use by our agents at all times. This means that if one DOC fails, the calls simply move to the other DOC, without losing the affected calls. Your service is never lost.